Rotary locking mechanism

ABSTRACT

A mechanism for immobilizing an arming shaft to preclude axial movement ofhe shaft until its release is desired, comprising a base and rotor mounted thereon. The rotor holds hardened metal balls in engagement with a circumferential groove on the shaft to lock the shaft in position. The base, rotor and shaft are held in locked position by an arming wire. Compression springs acting between the base and rotor cause relative rotation thereof, when the arming wire is removed, to an unlocked position where the balls can be forced into apertures in the base and release the shaft for axial movement.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to ball-lock mechanisms, and moreparticularly to ball-lock mechanisms which are unlocked by rotary asopposed to longitudinal motion.

2. Description of the Prior Art

Military weapons such as bombs, torpedoes, missiles and the like, arecustomarily provided with a safing-arming mechanism which enables theweapon to be maintained in a safe or unfirable condition duringhandling, and to enable arming of the weapon when it is ready for use.These safing-arming mechanisms frequently take the form of a shaft orrod which is movable axially from a safe to an armed position. Thearming shaft customarily carries either, an element of an explosivetrain held out of alignment to interrupt the explosive train when thearming shaft is in a safe position, or, a switch contact or contactswhich are held out of their arming positions when the arming rod is inthe safe position. A mechanism, such as a ball-lock mechanism, isprovided to hold the arming shaft in the safe position until it isdesired to arm the weapon.

Many prior art devices have used hardened metal balls to provide avariety of ball-lock mechanisms for arming shafts. These prior artdevices have all used essentially a longitudinal motion to operate theball-locking mechanism. This longitudinal motion is often undesirable.For weapons that are launched from aircraft and submarines, the methodof keeping an arming device locked at all times can be a problem. Inaddition to requiring more space, certain prior art longitudinal lockstended to protrude from the surface of the weapon case after actuationwhich would increase aerodynamic or hydrodynamic drag. Also, the priorart devices tend to reduce visibility of the arming shaft from theoutside of the weapon case, thus making visual observation of a safecondition difficult or impossible.

SUMMARY OF THE INVENTION

The present invention obviates the aforementioned difficulties, and alsoprovides means for visual observation of the shaft position to determinewhether it is in its locked or unlocked condition. The locking mechanismis easily controlled by means of an arming wire, safety lock, or safetybar usually associated with military weapons. The shaft is heldlongitudinally secure by hardened steel balls which are held in positionby the base member until release by the rotation of the rotor under theinfluence of two compression springs until reaching the limit stops. Theinternal diameter of the rotor is in two steps, the smaller holding thefour balls in a locked position and the larger diameter aligning theballs to move outward into apertures in the base member to free thegrooved arming shaft for longitudinal movement to the arming position.

STATEMENT OF THE OBJECTS OF THE INVENTION

It is a primary object of this invention to provide a ball-lockmechanism which is unlocked by rotary motion of the locking elements.

It is another objective of this invention to provide a rotary lockingmechanism for an arming shaft in which a single arming wire locks boththe rotary lock and shaft in safe position until the arming wire isremoved.

It is a further object of this invention to provide a rotary lockingmechanism in which the arming wire is restrained solely by the dragproduced by the locked mechanism.

It is yet another object of this invention to provide a rotary lockingmechanism for an arming shaft which may readily be visually inspected todetermine safe and unsafe conditions.

It is a still further object of this invention to provide a rotary lockfor arming shafts which may be maintained in a safe condition by meansof arming wires, lanyards, channel-shaped or forked brackets and othersimilar devices.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages and novel features of the invention willbecome readily apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawingswherein:

FIG. 1 is a plan view of the rotary locking mechanism of the presentinvention illustrating the various parts thereof in the unlockedposition;

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1 andillustrates additional details of the ball-lock mechanism;

FIG. 3 is a plan view of the side opposite that shown in FIG. 1 andillustrates the positions of the arming wire holes and the retainingring for mounting the mechanism in a weapon;

FIG. 4 is a view, partially in section, illustrating the butterflyconfiguration of the base member;

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4 andillustrates additional details of the base member;

FIG. 6 is a sectional view of the rotor illustrating various details ofits construction;

FIG. 7 is a plan view, partially in section, of the rotor shown in FIG.6 and illustrates the hemispherical recesses which receive the lockingballs when the mechanism is unlocked; and

FIG. 8 is a fragmentary view of the arming shaft which is locked by themechanism and illustrating the circumferential groove engaged by thelocking balls.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Attention now is directed to the drawings, wherein like numerals ofreference designate like parts throughout the several views, and moreparticularly to FIGS. 1 to 3 wherein there is illustrated the rotarylocking mechanism of the present invention designated generally by thereference numeral 10. The mechanism 10 comprises a base member 11, ofsubstantially butterfly configuration, and a rotor 12. The base member11 is provided with an axially extending hollow projection 14 which isreceived within a central aperture 15 formed in the rotor 12. Thecylindrical projection 14 may be best seen in FIGS. 4 and 5. The rotor12 is provided with a pair of axially extending projections 16 whichproject into the spaces between the wings of the butterfly configuredbase 11. The projections 16 may be seen in more detail in FIGS. 6 and 7.

A pair of compression springs 18 are fitted into blind apertures 19, inthe base 11, and blind apertures 20, in the projections 16, and normallyurge rotation of the base of the rotor 12, relative to the base 11, tothe unlocked position shown in FIG. 1. A pair of dowel pins 21 are fixedin the base 11 and serve to orient the mechanism 10 when it is mountedin a weapon (not shown). A retaining ring 22, mounted in a groove 24formed in the rotor 12, is provided for engagement with a groove in therecess provided in the weapon for the mechanism 10 to hold the mechanismin place.

A plurality of hardened metal balls 25, is disposed within apertures 26formed in the projection 14 of the base 11. The interior of the rotor 12is provided with a plurality of substantially hemispherical recesses 28(FIG. 7) which accommodate the balls 25 when the mechanism is unlocked.The recesses 28 are provided with tangent surfaces 29 to facilitatemovement of the balls into and out of the recesses 28.

OPERATION

In order that a better understanding of the invention might be had, itsmode of operation will now be described.

An arming shaft 31 (FIG. 8) is introduced into a central aperture 30formed in the projection 14 until a circumferential groove 32 in theshaft lies in the plane of the balls 25. The tip of the shaft 31 willthen be flush with the top surface of the rotor 12 as viewed in FIG. 3.The rotor 12 is then rotated relative to the base 11, clockwise in FIG.1 and counter-clockwise in FIG. 3, to compress the springs 18. Thisrotation causes the balls 25 to roll out of the recesses 28 along thetangent surfaces 29 until they engage the inside diameter of theaperture 15. The radially inward movement of the balls 25 forces thempartially through the apertures 26 into the central aperture 30 and intoengagement with the circumferential groove 32 in the shaft 31 as shownin FIG. 8. In this position, the balls 25 preclude any axial movement ofthe arming shaft 31. When the springs have been substantially fullycompressed, arming holes 34, 35 and 36, in the shaft 31, projection 14and rotor 12, respectively, will all be axially aligned and an armingwire or lanyard 38, shown in FIG. 3, may be inserted into these alignedholes to lock the mechanism and shaft in the safe positions. Themechanism is now locked with the arming shaft in the safe position untilremoval of the arming wire.

From the foregoing it will be readily apparent that the presentinvention possesses numerous advantages not found in prior art devices.For example, the rotary locking and unlocking motion is controllable byarming wires, or lanyards, as well as flat surfaces or channel-shapeddevices engaging the flat sides of the rotor 12, which are best seen inFIG. 3. Also, rotary motion instead of longitudinal motion to providethe locking action saves space and prevents unwanted protrusions as wellas affording compactness, high strength, durability and low parts count.Further, the mechanism of the present invention enables visualinspection of the shaft and lock conditions since the rotor 12 and tipof the shaft 31 can be flush with the surface of the weapon in which itis mounted. Additionally, redundant locking is provided since the shaft31 is locked in a safe position, not only by the rotary lockingmechanism, but also by the arming wire.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings and would readily occur tothose skilled in the art. For example, the invention could include meansto restrain the arming shaft from rotary motion as well as longitudinalmotion by using hemispherical holes or even counter-bores in the shaftso that the balls grip the shaft in all directions when locked. Also,soluble elements could be used to hold the rotary mechanism locked untildissolved under water for under water weapons. Further, a solenoid orexplosive actuator could also easily be utilized to release the rotarylock either from within the weapon or from the launch vehicle, and sinceaircraft often require the capability to jettison in a safe conditionthe pilot could be provided with means to operate a solenoid topermanently lock the rotary lock. Additionally, the shaft being lockedcould be of any appropriate size and shape and could be altered torelease inwardly or outwardly. Thus the present invention could beutilized as a release mechanism in separating a cable from its mountingor to fulfill any similar need to mechanically release one part fromanother with a simple rotary motion. It is therefore to be understoodthat within the scope of the appended claims the invention may bepracticed otherwise than as specifically described.

I claim:
 1. A rotary-acting, safing and arming, ball-lock mechanism forreleasably locking an arming shaft of a weapon against axial movement,said arming shaft having an engageable surface, comprising:a base memberhaving a central longitudinal aperture therein for receiving the armingshaft; a rotor mounted for limited rotary movement on said base member;a plurality of radial apertures formed in said base member andcommunicating with said central longitudinal aperture; a plurality ofballs disposed in said radial apertures; a plurality of cam surfacesformed on said rotor for moving said balls partially through said radialapertures into said central aperture and into engagement with the armingshaft engageable surface to lock the shaft against movement when saidrotor is moved to a safe position; means for locking said base memberand said rotor in the safe position; and a pair of compression springsinterposed between said base member and said rotor for moving said rotorto an arming position when said locking means is released whereby saidballs are free to disengage the arming shaft engageable surface, releasethe arming shaft and permit axial movement of the arming shaft to thearming position to arm the weapon.
 2. A mechanism as defined in claim 1wherein said base member is provided with a pair of dowel pins on theside opposite said rotor for positioning said mechanism when insertedinto a weapon.
 3. A mechanism as defined in claim 1 wherein said rotoris provided with a circumferential slot to accommodate a retaining ringfor holding said mechanism within a recess in a weapon.
 4. A mechanismas defined in claim 1 wherein said locking means comprises a pluralityof arming wire holes formed in said base member and said rotor, saidholes being axially aligned when said rotor is in the safe position;andan arming wire for insertion into the aligned holes for locking saidrotor in the safe position.
 5. A mechanism as defined in claim 4 whereinsaid base member is provided with a pair of dowel pins on the sideopposite said rotor for positioning said mechanism when inserted into aweapon; andsaid rotor is provided with a circumferential slot toaccommodate a retaining ring for holding said mechanism within a recessin the weapon.
 6. A rotary-acting, safing and arming, ball-lockmechanism for releasably locking a circumferentially-grooved armingshaft of a weapon against axial movement comprising:a base member ofsubstantially butterfly configuration having wing members and having acylindrical projection extending axially therefrom, said cylindricalprojection being provided with a central longitudinal aperture thereinfor receiving the arming shaft; a rotor mounted on said cylindricalprojection by means of a central aperture in said rotor for rotarymovement relative to said base member, said rotor being provided with apair of axial projections which extend between the wing members of thebutterfly configuration whereby rotary movement of the rotor is limited;a plurality of radial apertures formed in said cylindrical projectionand communicating with said central longitudinal aperture; a pluralityof substantially hemispherical recesses formed in the interior surfaceof the central aperture in said rotor and in the plane of said radialapertures; a plurality of balls disposed partially in said hemisphericalrecesses and partially in said radial apertures; a plurality of camsurfaces tangent to said hemispherical recesses for moving said ballsout of said hemispherical recesses and partially through said radialapertures into said central aperture and into engagement with thecircumferential groove of the arming shaft to lock the shaft againstaxial movement when said rotor is moved to a safe position; a pair ofarming wire holes formed in both said cylindrical projection and saidrotor, said arming wire holes being axially aligned when said rotor isin the safe position; an arming wire positioned in said arming wireholes for locking said rotor in the safe position; and a pair ofcompression springs interposed between the wing members of saidbutterfly configuration and the axial projections on said rotor formoving said rotor to an arming position when said arming wire is removedwhereby said balls are free to move back into said hemisphericalrecesses through said radial apertures to release the arming shaft andpermit axial movement thereof to the arming position to arm the weapon.